Methods and compositions for diagnosis and treatment of malignant and non-malignant gammopathies

Abstract

The invention relates, at least in part, to the identification of paratarg as a paraprotein target in various malignant and non-malignant gammopathies, which can be used in the diagnosis and treatment of either.

The invention claimed is: 
     
       1. A method comprising
 determining a level of a paraprotein that selectively binds to phosphorylated paratarg (stomatin-like protein 2) in a body fluid of a subject, optionally wherein the body fluid is blood, serum, lymph, saliva, urine or cerebrospinal fluid, and 
 comparing said level of said paraprotein to a reference or control level, 
 wherein if the level of said paraprotein in said body fluid is higher than the reference or control level, then the subject is indicated as having a gammopathy, and 
 wherein if the level of said paraprotein in said body fluid is not substantially different from the reference or control level, then the subject is not indicated as having a gammopathy; 
 optionally wherein the step of determining the level of the paraprotein comprises mixing or contacting said sample with a reagent that selectively binds to said paraprotein, said paraprotein selectively binding said paratarg, and/or contacting said sample with a device for assaying the level of one or more of said specific paraprotein/s. 
 
     
     
       2. The method of  claim 1 , wherein the level of said paraprotein that selectively binds said paratarg is determined by an immunoassay, comprising:
 contacting said body fluid with an antibody that selectively binds said paraprotein, and 
 detecting and/or quantifying the binding of said antibody to said paraprotein; 
 wherein said immunoassay is a western blotting assay, an enzyme-linked immunosorbent assay (ELISA), an enzyme-linked immunospot assay (ELISPOT), a lateral flow test assay, an enzyme immunoassay (EIA), a fluorescent polarization immunoassay (FPIA), a chemiluminescent immunoassay (CLIA), an antibody sandwich capture assay, or an isoelectric focusing assay. 
 
     
     
       3. The method of  claim 1 , wherein the level of the paraprotein that selectively binds to said paratarg is determined by an immunoassay, comprising
 contacting said body fluid with paratarg, or an epitope thereof, or phosphorylated paratarg, or an epitope thereof, and 
 detecting and/or quantifying the binding of said paratarg, or epitope thereof, or phosphorylated paratarg, or epitope thereof, to said paraprotein; 
 optionally wherein the paratarg is human paratarg (SEQ ID NO: 1) (RefSeq: NP_038470); and/or 
 optionally wherein said immunoassay is a western blotting assay, an enzyme-linked immunosorbent assay (ELISA), an enzyme-linked immunospot assay (ELISPOT), a lateral flow test assay, an enzyme immunoassay (EIA), a fluorescent polarization immunoassay (FPIA), a chemiluminescent immunoassay (CLIA), an antibody sandwich capture assay, or an isoelectric focusing assay. 
 
     
     
       4. The method of  claim 3  wherein the paratarg or epitope thereof used to contact the paraprotein comprises a substitution of one or more amino acid residues amenable to phosphorylation with a different amino acid residue mimicking phosphorylation of said paratarg or epitope thereof;
 optionally, wherein the paratarg or epitope thereof used to contact the paraprotein comprises a substitution of one or more serine residues of amino acids 13-31 of human paratarg (SEQ ID NO: 1). 
 
     
     
       5. The method of  claim 4 , wherein the paratarg or epitope thereof used to contact the paraprotein comprises a substitution of one or more Ser residues of amino acids 17-31 of human paratarg (SEQ ID NO: 1) with a Glu or Asp or Phe residue. 
     
     
       6. The method of  claim 5 , wherein the paratarg or epitope thereof used to contact the paraprotein comprises a substitution of 17Ser of human paratarg (SEQ ID NO: 1) with a Glu or Asp or Phe residue. 
     
     
       7. The method of  claim 1 , wherein the paratarg is phosphorylated paratarg, optionally, wherein the paratarg is phosphorylated on/in one or more of amino acids 17-31 of human paratarg (SEQ ID NO: 1), or wherein the paratarg is phosphorylated on amino acid 17 (Ser) of human paratarg (SEQ ID NO: 1). 
     
     
       8. A method comprising determining a level of phosphorylated paratarg (stomatin-like protein 2) in a body fluid, cell, or tissue of a subject, optionally wherein the body fluid is blood, serum, lymph, saliva, urine or cerebrospinal fluid, and
 comparing said level of paratarg to a reference or control level, 
 wherein if the level of paratarg in the subject is higher than the reference or control level, then the subject is indicated as having a gammopathy, and 
 wherein if the level of paratarg is not substantially different from the reference or control level, then the subject is not indicated as having a gammopathy; 
 optionally wherein the step of determining the level of paratarg comprises mixing or contacting said sample with a reagent that selectively binds to paratarg, and/or contacting said sample with a device for assaying the level of paratarg. 
 
     
     
       9. The method of  claim 8 , wherein the level of paratarg is determined by an immunoassay, comprising
 contacting said body fluid with an antibody that selectively binds paratarg, and 
 detecting and/or quantifying the binding of said antibody to paratarg; 
 optionally wherein said immunoassay is a western blotting assay, an enzyme-linked immunosorbent assay (ELISA), an enzyme-linked immunospot assay (ELISPOT), a lateral flow test assay, an enzyme immunoassay (EIA), a fluorescent polarization immunoassay (FPIA), a chemiluminescent immunoassay (CLIA), an antibody sandwich capture assay, or an isoelectric focusing assay. 
 
     
     
       10. The method of  claim 8 , wherein the paratarg is phosphorylated paratarg, optionally, wherein the paratarg is phosphorylated on/in one or more of amino acids 17-31 of human paratarg (SEQ ID NO: 1), or wherein the paratarg is phosphorylated on amino acid 17 (Ser) of human paratarg (SEQ ID NO: 1). 
     
     
       11. An isolated antibody or antigen-binding fragment thereof that selectively binds a paraprotein, wherein the paraprotein selectively binds phosphorylated paratarg (stomatin-like protein 2). 
     
     
       12. A composition comprising the isolated antibody or antigen-binding fragment thereof of  claim 11 , optionally wherein the composition comprises a pharmaceutically acceptable carrier. 
     
     
       13. An isolated antibody or antigen-binding fragment thereof that selectively binds phosphorylated paratarg (stomatin-like protein 2) or a phosphorylated epitope thereof. 
     
     
       14. A composition comprising the isolated antibody or antigen-binding fragment thereof of  claim 13 , optionally wherein the composition comprises a pharmaceutically acceptable carrier. 
     
     
       15. A kit for detecting paratarg (stomatin-like protein 2), or an epitope thereof, or a paraprotein, or fragment thereof, that selectively binds paratarg, comprising
 the antibody, or fragment thereof, of  claim 11 . 
 
     
     
       16. A kit for detecting paratarg (stomatin-like protein 2), or an epitope thereof, or a paraprotein, or fragment thereof, that selectively binds paratarg, comprising
 the antibody, or fragment thereof, of  claim 13 .